Aspects of membrane function and assembly will be studied in Staphylococcus aureus and Spirillum itersonii. The relationship between the cytoplasmic and membrane associated nitrate reductase in S. aureus will be pursued. The role of hemoproteins in regulating the formation of membrane associated respiratory enzymes will be studied in heme-deficient mutants. In S. itersonii the relationship of iron reductase to the membrane associated respiratory chain will be studied. BIBLIOGRAPHIC REFERENCES: Lascelles, J. The regulation of heme and chlorophyll synthesis in bacteria. Ann. N.Y. Acad. Sci. 244: 334-347 (1975). Burke, K.A., and J. Lascelles. Nitrate reductase system in Staphylococcus aureus wild type and mutants. J. Bacteriol. 123:308-316 (1975).